Full local backup infrastructure

This is the basic infrastructure for pulling a full(*) backup of the
device's data over an adb(**) connection to the local device.  The
basic process consists of these interacting pieces:

1. The framework's BackupManagerService, which coordinates the
   collection of app data and routing to the destination.

2. A new framework-provided BackupAgent implementation called
   FullBackupAgent, which is instantiated in the target applications'
   processes in turn, and knows how to emit a datastream that contains
   all of the app's saved data files.

3. A new shell-level program called "bu" that is used to bridge from
   adb to the framework's Backup Manager.

4. adb itself, which now knows how to use 'bu' to kick off a backup
   operation and pull the resulting data stream to the desktop host.

5. A system-provided application that verifies with the user that
   an attempted backup/restore operation is in fact expected and to
   be allowed.

The full agent implementation is not used during normal operation of
the delta-based app-customized remote backup process.  Instead it's
used during user-confirmed *full* backup of applications and all their
data to a local destination, e.g. via the adb connection.

The output format is 'tar'.  This makes it very easy for the end
user to examine the resulting dataset, e.g. for purpose of extracting
files for debug purposes; as well as making it easy to contemplate
adding things like a direct gzip stage to the data pipeline during
backup/restore.  It also makes it convenient to construct and maintain
synthetic backup datasets for testing purposes.

Within the tar format, certain artificial conventions are used.
All files are stored within top-level directories according to
their semantic origin:

apps/pkgname/a/  : Application .apk file itself
apps/pkgname/obb/: The application's associated .obb containers
apps/pkgname/f/  : The subtree rooted at the getFilesDir() location
apps/pkgname/db/ : The subtree rooted at the getDatabasePath() parent
apps/pkgname/sp/ : The subtree rooted at the getSharedPrefsFile() parent
apps/pkgname/r/  : Files stored relative to the root of the app's file tree
apps/pkgname/c/  : Reserved for the app's getCacheDir() tree; not stored.

For each package, the first entry in the tar stream is a file called
"_manifest", nominally rooted at apps/pkgname.  This file contains some
metadata about the package whose data is stored in the archive.

The contents of shared storage can optionally be included in the tar
stream. It is placed in the synthetic location:

shared/...

uid/gid are ignored; app uids are assigned at install time, and the
app's data is handled from within its own execution environment, so
will automatically have the app's correct uid.

Forward-locked .apk files are never backed up.  System-partition
.apk files are not backed up unless they have been overridden by a
post-factory upgrade, in which case the current .apk *is* backed up --
i.e. the .apk that matches the on-disk data.  The manifest preceding
each application's portion of the tar stream provides version numbers
and signature blocks for version checking, as well as an indication
of whether the restore logic should expect to install the .apk before
extracting the data.

System packages can designate their own full backup agents.  This is
to manage things like the settings provider which (a) cannot be shut
down on the fly in order to do a clean snapshot of their file trees,
and (b) manage data that is not only irrelevant but actively hostile
to non-identical devices -- CDMA telephony settings would seriously
mess up a GSM device if emplaced there blind, for example.

When a full backup or restore is initiated from adb, the system will
present a confirmation UI that the user must explicitly respond to
within a short [~ 30 seconds] timeout.  This is to avoid the
possibility of malicious desktop-side software secretly grabbing a copy
of all the user's data for nefarious purposes.

(*) The backup is not strictly a full mirror.  In particular, the
    settings database is not cloned; it is handled the same way that
    it is in cloud backup/restore.  This is because some settings
    are actively destructive if cloned onto a different (or
    especially a different-model) device: telephony settings and
    AndroidID are good examples of this.

(**) On the framework side it doesn't care that it's adb; it just
    sends the tar stream to a file descriptor.  This can easily be
    retargeted around whatever transport we might decide to use
    in the future.

KNOWN ISSUES:

* the security UI is desperately ugly; no proper designs have yet
  been done for it
* restore is not yet implemented
* shared storage backup is not yet implemented
* symlinks aren't yet handled, though some infrastructure for
  dealing with them has been put in place.

Change-Id: Ia8347611e23b398af36ea22c36dff0a276b1ce91

4 files changed, 324 insertions, 0 deletions

diff --git a/cmds/bu/Android.mk b/cmds/bu/Android.mk
new file mode 100644
index 0000000..4fd5fec
--- /dev/null
+++ b/cmds/bu/Android.mk
@@ -0,0 +1,18 @@
+# Copyright 2011 The Android Open Source Project
+#
+LOCAL_PATH:= $(call my-dir)
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := $(call all-subdir-java-files)
+LOCAL_MODULE := bu
+LOCAL_MODULE_TAGS := optional
+include $(BUILD_JAVA_LIBRARY)
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := bu
+LOCAL_SRC_FILES := bu
+LOCAL_MODULE_CLASS := EXECUTABLES
+LOCAL_MODULE_TAGS := optional
+include $(BUILD_PREBUILT)
+
+
diff --git a/cmds/bu/NOTICE b/cmds/bu/NOTICE
new file mode 100644
index 0000000..becc120
--- /dev/null
+++ b/cmds/bu/NOTICE
@@ -0,0 +1,190 @@
+
+   Copyright (c) 2011, The Android Open Source Project
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
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+
+      "Work" shall mean the work of authorship, whether in Source or
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+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
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+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
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+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
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+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
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+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
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+      where such license applies only to those patent claims licensable
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+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
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+      (d) If the Work includes a "NOTICE" text file as part of its
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+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
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+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
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+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
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+      defend, and hold each Contributor harmless for any liability
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+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
diff --git a/cmds/bu/bu b/cmds/bu/bu
new file mode 100755
index 0000000..e8dbc31
--- /dev/null
+++ b/cmds/bu/bu
@@ -0,0 +1,6 @@
+# Script to start "bu" on the device
+#
+base=/system
+export CLASSPATH=$base/framework/bu.jar
+exec app_process $base/bin com.android.commands.bu.Backup "$@"
+
diff --git a/cmds/bu/src/com/android/commands/bu/Backup.java b/cmds/bu/src/com/android/commands/bu/Backup.java
new file mode 100644
index 0000000..2b8d6aa
--- /dev/null
+++ b/cmds/bu/src/com/android/commands/bu/Backup.java
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.commands.bu;
+
+import android.app.backup.IBackupManager;
+import android.os.ParcelFileDescriptor;
+import android.os.RemoteException;
+import android.os.ServiceManager;
+import android.util.Log;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+import java.util.ArrayList;
+
+public final class Backup {
+    static final String TAG = "Backup";
+
+    private static String[] mArgs;
+    private int mNextArg;
+
+    public static void main(String[] args) {
+        mArgs = args;
+        try {
+            new Backup().run();
+        } catch (Exception e) {
+            Log.e(TAG, "Error running backup", e);
+        }
+        Log.d(TAG, "Finished.");
+    }
+
+    public void run() {
+        IBackupManager bmgr = IBackupManager.Stub.asInterface(ServiceManager.getService("backup"));
+        if (bmgr == null) {
+            System.err.println("ERROR: could not contact backup manager");
+            return;
+        }
+
+        ArrayList<String> packages = new ArrayList<String>();
+        boolean saveApks = false;
+        boolean saveShared = false;
+        boolean doEverything = false;
+
+        String arg;
+        while ((arg = nextArg()) != null) {
+            
+            if (arg.startsWith("-")) {
+                if ("-apk".equals(arg)) {
+                    saveApks = true;
+                } else if ("-noapk".equals(arg)) {
+                    saveApks = false;
+                } else if ("-shared".equals(arg)) {
+                    saveShared = true;
+                } else if ("-noshared".equals(arg)) {
+                    saveShared = false;
+                } else if ("-all".equals(arg)) {
+                    doEverything = true;
+                } else {
+                    System.err.println("ERROR: unknown flag " + arg);
+                    return;
+                }
+            } else {
+                // Not a flag; treat as a package name
+                packages.add(arg);
+            }
+        }
+
+        if (doEverything && packages.size() > 0) {
+            System.err.println("ERROR: -all used with specific package set");
+            return;
+        }
+
+        if (!doEverything && packages.size() == 0) {
+            System.err.println("ERROR: no packages supplied and -all not used");
+            return;
+        }
+
+        try {
+            ParcelFileDescriptor fd = ParcelFileDescriptor.dup(FileDescriptor.out);
+            String[] packArray = new String[packages.size()];
+            bmgr.fullBackup(fd, saveApks, saveShared, doEverything, packages.toArray(packArray));
+        } catch (IOException e) {
+            System.err.println("ERROR: cannot dup System.out");
+        } catch (RemoteException e) {
+            System.err.println("ERROR: unable to invoke backup manager service");
+        }
+    }
+
+    private String nextArg() {
+        if (mNextArg >= mArgs.length) {
+            return null;
+        }
+        String arg = mArgs[mNextArg];
+        mNextArg++;
+        return arg;
+    }
+}
\ No newline at end of file